Copper fungicides and process of producing same



Patented Dec. 21, 1948 COPPER FUNGICIDES AND PROCESS OF PRODUCING SAME Alexander A. Nikitin, College Park, Ga., assignor to Tennessee Copper Company, New York, N. Y., a corporation of New Jersey No Drawing.

4 Claims. 1

This invention relates to fungicides and comprises a new and useful fungicide and the process of making the same.

This application is a continuation-in-part of my application Serial No. 544,475, filed July 11, 1944, now abandoned which in turn was a division of my application Serial No. 448,846, filed June 27, 1942, now Patent No. 2,414,660.

Fungicides are well known in which copper enters as an element such, for example, as Bordeaux mixtures. When a fungicide is sprayed on a crop it should be uniformly and evenly distributed over the entire surface of the crop to be effective and should efficiently adhere thereto, should stand what is called weathering," and should be free from any injurious eflect upon the crop. All fungicides with which I am familiar and in which copper entersas an active ingredient are lacking in one or more of these essentials. Furthermore, some of the fungicides are composed of a plurality of constitutents which have to be mixed by an attendant when they are applied to the crop, and unless they are mixed in proper proportions and in the proper way their efliciency is reduced if not destroyed. They are undesirable for this reason.

Repeated attempts have been made with slight success to improve the physical properties of basic copper sulphate by the addition of supplementary materials such as vegetable flour. The addition of the alkali salts of protein substances such as 'It should be emphasized that the deleterious action of alkali was not confined to the poor adherence only but it also rendered basic copper sulphate incompatible with organic insecticides, such as derris or pyrethrum. Further the handling of these protein substances for spray application required skill and knowledge not possessed by the average farmer.

The effort to introduce the protein substances such as casein failed when the casein was used without excessive amount of alkali since the final product was not readily wettable.

The present invention has for its object to provide a fungicide in which copper enters as an effective ingredient, which has highly toxic properties; which is chemically stable in the pres- Application November 12, 1947, Serial No. 785,535

ence of alkalis such as lime and which is stable upon exposure to atmospheric action; which is readily wettable, and has good spreading and adhering properties; which is free of injurious effects on the crop; and which is ready to be applied to the crop by dusting or by merely dispersing the same in a suitable amount of water.

It was found that when a solution of a copper salt and an aluminum salt is precipitated with an alkali solution containing soya bean protein, or soaps of the fatty acids, the resultant copper alumino compound possesses, greatly improved physical properties, such as'spreading, sticking and dispersion, as well as high toxicity.

These new copper fungicides are copper alumino salts in which part of the aluminum may combine with the protein or fatty acid radical but in which aluminum is also present in'the form of aluminum hydrate (which may change gradually to alumina) as has been proved by chemical analyses. The soya bean protein or soaps of fatty acids is combined with the copper. through the aid of the alumina, to form the new compound which possesses greatly improved physical and chemical properties. The new copper fungicides are stable chemically when they are exposed to atmospheric action. They are compatible with lime and lead arsenate plus lime. They are also compatible with oil emulsions and with organic insecticides such as pyrethrum and rot'enone. They also retain their neutral character in water suspension, and during storage.

The procedure which is followed in the preparation of the improved fungicide involves dissolving a copper salt in water with an aluminum salt, which is for convenience designated solution A.

I then introduce into a suitable amount of water a protein-containing material preferably soya bean flour (about 50% protein) or soaps of of a fatty acid such as oleic, stearic or linoleic, together with an alkali such as ammonium hydroxide. The protein or the soaps form salts with the alkali. This for convenience I designate solution B.

I then add solution B to solution A until the resulting slurry is approximately neutral (pH 6.8-6.9) thereby precipitating a basic copper sulphate-alumina-proteinate. This precipitate is filtered and the filter cake is reducedto a finely divided powder, and it is then ready for use. This finely divided basic copper sulphate-aluminadispersed in water at various concentrations dean -m7 pending upon the crop and the extent of the (CuSO4.5H2O) or the amount of aluminum sulphate may be decreased to any desired extent down to 5 parts of aluminum sulphate to 100 parts of copper sulphate.

In making solution B the concentration may be varied according to the character of the alkali used, since the amount of alkali used will depend upon the ratio between the copper sulphate and aluminum sulphate employed. In actual practice it is necessary to add solution B to solution A until complete precipitation takes place at about pH 6.8, which pH should not be substantially departed from in order to avoid the formationof soluble cuproammonium compounds which form with an excess of ammonia. If the pH of the slurry is carried beyond that point the complete precipitation of the components will not be secured.

For the purpose of illustrating one embodiment of the inventive idea reference is made to the following example, but it is to be expressly understood that the invention is not limited to this specific example. The choice of the copper salt and aluminum salt to be used in solution A may be varied. The proportions of aluminum sulphate may be varied anywhere within 5% to approximately 30% of the copper sulphate employed. This gives from 1% to alumina (A1203) in the finished product. Moreover any protein-bearing material, whether vegetable or animal, as well as. soaps of fatty acids may be employed and the, percentage thereof varied. However, the amount of protein material or soap in solution B should be such as to give from 0.5 to 3.5% protein or soap in the finished product.

As an example, dissolve in water 100 grams of copper sulphate and 25 grams of aluminumsulphate thus forming solution A. Then dissolve 0.5 to 3.5 grams of soap of a fatty acid and 40 grams of ammonium hydroxide about 25% of NH: in water, thus forming solution 13. Then add solution B to solution A until the resulting slurry reaches a pH of approximately 6.8, then filter the resulting precipitate and reduce it to a fine powder.

I discovered that when the aluminum and copper salts were precipitated in one operation with an alkali solution containing soyabean protein or the soap of a fatty acid they formed a copper alumino compound which furnished a higher amount of soluble copper and consequently was more effective in the control of fungus disease. Basic copper sulphate in the commonly available copper fungicides when in water suspension forms about 1.5 parts per million of soluble copper, which is not sufficient for the effective control of fungus disease. The amount of soluble copper is increased by the use of soya flour protein or soap of a fatty acid to about 24.5 parts per million. This is superior to-calcium caseinate which increases the amount of soluble copper to 103.6 parts per million but it'has such an inferior tenacity coeflicient that soya bean protein is superior in performance,

It was noted that when a copper sulphate solution was precipitated with an alkali solution containing soya bean protein or soaps of fatty acids but without alumina, the resultant copper compounds such as basic copper sulphate or carbonate plus copper proteinate are practically unwettable by water. Further these compounds showed a re duced toxicity to spore germination, which is at; tributed to their. lower wettability by water. When, however, soya bean protein or soaps of fatty acids are added to the alkali solution and an aluminum salt is precipitated in combination with copper sulphate, the resultant copper compound is readily wettable.

The orientation of the molecules in the surfaces is a material factor in the wetting of the soya bean protein or the soaps of the fatty acids which are introduced into the copper fungicides. Ap parently the hydrophilic, or friendly-to-water ends of the fatty acidmolecules when they are precipitated in combination with.the aluminum salt, are turned outward in the surf ce in such condition that they are easily wettab e; by water.

, inward in the surface.

When a soluble aluminum salt is added to the copper sulphate solution and then precipitated with an alkali solution containing soya bean pro- 2 tein, or the soaps of fatty acids, the resultant copper compounds, such as basic copper aluminocarbonate and alumino-sulphate containing soya bean protein or soaps of fatty acids show greatly improved spreading and adherence properties. When an aluminum salt and copper sulphate solution are co-precipitated with an alkali free from soya bean protein or spaps of fatty acids, the resultant copper compound does not show any improvement in spreading properties. The best spreading and sticking properties are obtained when soya bean protein or soaps of fatty acids and a soluble aluminum salt are introduced into the copper sulphate solution before the precipitation of the copper compound has taken place. Particularly good results were secured in spore germination tests and in the spray field in the control of bitter rot on apples with basic copper sulphate-alumina-proteinate.

The copper fungicides of the present invention as proved by increased yield of celery crops which are extremely sensitive to blight infection. This was in contrast to regular basic copper'sulphate.

It is again emphasized that the spreading and adhesive properties of the new copper fungicide are superior to those of either the regular basic copper sulphate compounds or the compounds of copper and aluminum without protein or soaps of fatty acids. This is of great importance in order to insure completeness of contact between the pathogenic organism and the spray residue and especially so when used on glossy citrus leaves. Further these improved fungicides are readily dispersed in water and they will remain in suspension without the addition of an auxiliary dispersing agent.

The new copper fungicides have a much higher chemical stability when used in combination with insecticides such as arsenical compounds, pyrethrum and rotenone. When commonly available basic copper-sulphates are used with arsenical compounds in a spray mixture it is required that lime should be used to reduce arsenical injury.

The use of lime in this case reduces the eflectiveness of the copper fungicide due to chemical interaction with the copper fungicide which has a tendency to decompose, as shown by its blackening, when it is in water suspension in combination with arsenicals plus lime. On the other hand, the new copper fungicide is compatible with lime and arsenicals and the fungicide remains stable and its effectiveness remains substantially unchanged. The buffering action toward weak organic acids makes these copper compounds safer to use on fruit and foliage, and thus extends their use to a greater variety of plants.

, It should be noted that when the alumina (A1203) content is reduced .to 1% and no protein or soaps of fatty acids is present the adherence property is only slightly improved and the covering property shows no improvement as compared with regular basic copper sulphate. Further when the alumina content of the final prod not is increased to about and no protein or soaps of fatty acids is present the adherence of the resultant basic copper-alumino-sulphate or copper alumino-carbonate is reduced. When the A1203 content is in a range between 1 and 10%, and the soya bean protein or soaps of fatty acids is in a range between 0.5 and 3.5% on the copper carbonate, or copper alumino compounds without protein or soaps of fatty acids. When no alumina is present the resultant basic copper sulphate or copper carbonate containing protein or soaps of fatty acids is repellent to water. This is especially true when the protein or soaps of fatty acids content of the compounds is above 1%. On the other hand, when a mixture of copper sulphate and aluminum sulphate is precipibated with an alkali, containing soya bean protein or soaps of fatty acids, the resultant basic copper alumino-sulphate or copper aluminocarbinate is readily wettable by water. The presence of the alumina changes the properties of the resultant copper compound in the presence of the protein or soaps of fatty acids group from hydrophobic to hydrophllic.

It is to be understood that other copper and aluminum compounds can be used in place of copper sulphate and aluminum sulphate, maintaining the same ratio between CuO and A1203. In general, any water-soluble copper and aluminum salts may be employed which produce the desired basic copper-alum'ino precipitates. In addition to copper sulphate, one may use copper chloride, copper nitrate, copper fluoride. copper iiluosilicate, copper lactate etc. In addition to aluminum sulphate, one/may use aluminum the bases of sodium, potassium, calcium or magnesium. In place of soya bean flour (which contains about 53.6% protein), equivalent amounts of dried skim milk, wheat flour, etc., or soaps of fatty acids such as oleic, stearic and linoleic may be used.

The present application embodies claims to the species including aluminum and soaps of fatty acids instead of proteins, the copper-alumino-protein species being claimed in my said application Serial Number 448,846, now Patent No. 2,414,660, and the copper-zinc-protein species being claimed in a division thereof, Serial No. 500,149, filed August 26, 1943, now Patent No. 2,414,661. Claims to the species including zinc and soaps of fatty acids are embodied in my copending application Serial No. 606,878, filed July 24, 1945.

What is claimed is:

1. The process of manufacturing copper fungicides which comprises reacting an aqueous solution of copper and aluminum salts with an alkali and a fatty acid soap, said copper salt beng selected from the group consisting of copper sulphate, copper chloride, copper nitrate, copper fluoride, copper fiuosilicate and copper lactate, and said aluminum salts being selected'from the group consisting of aluminum sulphate, aluminum chloride, sodium aluminate, and normal aluminum acetate, said reactants being in the proportions of parts copper salt to 5-30 parts aluminum salt to 0.5-3.5 parts fatty acid soap, alkali being added' until the solution becomes approximately neutral thereby precipitating a basic copper-alumina-soap compound.

2. The process of manufacturing copper fungicides which comprises reacting an aqueous solution of copper and aluminum sulphates with an alkali and a soap of a fatty acid in the proportions of 100 parts copper sulphate to 5-30 parts aluminum sulphate to 0.5-3.5 parts fatty acid soap, alkali being added until the solution becomes approximately neutral thereby precipitating a basic copper-alumina-soap compound.

3. A copper fungicide containing a major proportion of a basic copper salt together with 1- 10% alumina and 05-35% fatty acid soap, said basic copper salt being of the group consisting of basic copper sulphate, chloride, nitrite, fluoride, fluosilicate and lactate.

4. A copper fungicide containing a major proportion of basic copper sulphate together with 1-10% alumina and 0.5-3.5% fatty acid soap.

ALEXANDER. A. NIKITIN.

No references cited. 

